Overmolded protective leaching mask assemblies and methods of use

ABSTRACT

Embodiments of the invention relate generally to overmolded protective leaching masks, and methods of manufacturing and using the same for leaching superabrasive elements such as polycrystalline diamond elements. In an embodiment, a protective leaching mask assembly includes a superabrasive element including a central axis and a superabrasive table, and a protective mask overmolded onto at least a portion of the superabrasive element. The protective mask includes a base portion and at least one sidewall extending from the base portion and defining an opening generally opposite the base portion. The at least one sidewall includes an inner surface configured to abut with a selected portion of the superabrasive element being chemically resistant to a leaching agent and an outer surface sloping at an oblique angle relative to the central axis.

BACKGROUND

Wear-resistant, superabrasive materials are traditionally utilized for avariety of mechanical applications. For example, polycrystalline diamond(“PCD”) materials are often used in drilling tools (e.g., cuttingelements, gage trimmers, etc.), machining equipment, bearingapparatuses, wire-drawing machinery, and in other mechanical systems.

Conventional superabrasive materials have found utility as superabrasivecutting elements in rotary drill bits, such as roller cone drill bitsand fixed-cutter drill bits. A conventional cutting element may includea superabrasive layer or table, such as a PCD table. The cutting elementmay be brazed, press-fit, or otherwise secured into a preformed pocket,socket, or other receiving space formed in the rotary drill bit. Inanother configuration, the substrate may be brazed or otherwise joinedto an attachment member such as a stud or a cylindrical backing.Generally, a rotary drill bit may include one or more PCD cuttingelements affixed to a bit body of the rotary drill bit.

As mentioned above, conventional superabrasive materials have foundutility as bearing elements in thrust-bearing and radial bearingapparatuses. A conventional bearing element typically includes asuperabrasive layer or table, such as a PCD table, bonded to asubstrate. One or more bearing elements may be mounted to a bearingrotor or stator by press-fitting, brazing, mechanically coupled, orthrough other suitable methods of attachment. Typically, bearingelements mounted to a bearing rotor have superabrasive faces configuredto contact corresponding superabrasive faces of bearing elements mountedto an adjacent bearing stator.

Cutting elements having a PCD table may be formed and bonded to asubstrate using an ultra-high pressure, ultra-high temperature (“HPHT”)sintering process. Often, cutting elements having a PCD table arefabricated by placing a cemented carbide substrate, such as acobalt-cemented tungsten carbide substrate, into a container orcartridge with a volume of diamond particles positioned on a surface ofthe cemented carbide substrate. A number of such cartridges may beloaded into an HPHT press. The substrates and diamond particle volumesmay then be processed under HPHT conditions in the presence of acatalyst material that causes the diamond particles to bond to oneanother to form a diamond table having a matrix of bonded diamondcrystals. The catalyst material is often a metal-solvent catalyst, suchas cobalt, nickel, or iron, which facilitates intergrowth and bonding ofthe diamond crystals.

In one conventional approach, a constituent of the cemented-carbidesubstrate, such as cobalt from a cobalt-cemented tungsten carbidesubstrate, liquefies and sweeps from a region adjacent to the volume ofdiamond particles into interstitial regions between the diamondparticles during the HPHT process. The cobalt may act as a catalyst tofacilitate the formation of bonded diamond crystals. A metal-solventcatalyst may also be mixed with a volume of diamond particles prior tosubjecting the diamond particles and substrate to the HPHT process.

The presence of the metal-solvent catalyst and/or other materials in thediamond table may reduce the thermal stability of the diamond table atelevated temperatures. For example, the difference in thermal expansioncoefficient between the diamond grains and the metal-solvent catalyst isbelieved to lead to chipping or cracking in the PCD table of a cuttingelement during drilling or cutting operations. The chipping or crackingin the PCD table may degrade the mechanical properties of the cuttingelement or lead to failure of the cutting element. Additionally, at hightemperatures, diamond grains may undergo a chemical breakdown orback-conversion with the metal-solvent catalyst. Further, portions ofdiamond grains may transform to carbon monoxide, carbon dioxide,graphite, or combinations thereof, thereby degrading the mechanicalproperties of the PCD material.

Accordingly, it is desirable to remove metal-solvent catalyst from a PCDmaterial in situations when the PCD material may be exposed to hightemperatures. Chemical leaching is often used to dissolve and removevarious materials from the PCD layer. For example, chemical leaching maybe used to remove metal-solvent catalysts, such as cobalt, from regionsof a PCD layer that may experience elevated temperatures duringdrilling, such as regions adjacent to the working surfaces of the PCDlayer.

Conventional chemical leaching techniques often involve the use ofhighly concentrated and corrosive solutions, such as highly acidicsolutions, to dissolve and remove metal-solvent catalysts frompolycrystalline diamond materials. However, in addition to dissolvingmetal-solvent catalysts from a PCD material, leaching solutions may alsodissolve any accessible portions of a substrate to which the PCDmaterial is attached. For example, highly acidic leaching solutions maydissolve any accessible portions of a cobalt-cemented tungsten carbidesubstrate, causing undesired pitting and/or other corrosion of thesubstrate surface.

In some conventional leaching techniques, a polymeric leaching cup maybe placed around a portion of a PCD element to protect the substratefrom a leaching solution. A polymeric leaching cup may, for example,surround the substrate surface and a portion of the PCD layer near thesubstrate. Such leaching cups may not, however, provide adequateprotection under various leaching conditions. It may be desirable toexpose PCD articles to leaching solutions for varying periods of timeand/or to expose the PCD articles to leaching solutions under varioustemperature and/or pressure conditions to obtain specified leach depths.While various temperatures, pressures, and leach times may enableleaching of a PCD article to a desired degree, such conditions mayundesirably cause portions of the substrate of the PCD article to beexposed to a leaching solution. For example, a leaching solution maypass between portions of the cup and the PCD article, resulting inportions of the substrate or other protected part of the PCD articlebeing exposed to the leaching solution. Additionally, gases, such asair, may be trapped between a leaching cup and a PCD article when thecup is placed around the PCD article. During leaching, trapped gases mayexpand due to an increase in temperature and/or a decrease in pressure,pushing the PCD article out of the leaching cup and exposing a portionof the substrate or other protected part of the PCD article to theleaching solution. Such exposure to leaching solutions may result inundesired corrosion and/or damage to PCD substrates.

U.S. patent application Ser. No. 12/555,715 (now published as U.S.Patent Application Publication No. 2011/0056141) discloses otherexamples of processing superabrasive elements that include the use ofprotective layers formed on portions of the superabrasive elements. Thedisclosure of U.S. patent application Ser. No. 12/555,715 isincorporated herein, in its entirety, by this reference.

SUMMARY

Embodiments of the invention relate generally to protective leachingmask assemblies and methods of using such protective leaching maskassemblies to at least partially leach a superabrasive element. In anembodiment, a protective leaching mask assembly may include asuperabrasive element including a central axis and a superabrasivetable. The assembly may further include a protective mask overmoldedonto at least a portion of the superabrasive element. The protectivemask may include a base portion and at least one sidewall extending fromthe base portion and defining an opening generally opposite the baseportion. The at least one sidewall may include an inner surface thatabuts with a selected portion of the superabrasive element beingchemically resistant to a leaching agent. The at least one sidewall mayfurther include an outer surface sloping at an oblique angle relative tothe central axis of the superabrasive element.

In an embodiment, a protective leaching mask assembly may include asuperabrasive element including a central axis and a superabrasivetable. The assembly may further include a protective mask overmoldedonto at least a portion of the superabrasive element. The protectivemask may be chemically resistant to a leaching agent and may include abase portion and at least one sidewall extending from the base portionand defining an opening generally opposite the base portion. The atleast one sidewall may include an inner surface abutting a selectedportion of the superabrasive element and an outer surface sloping at anoblique angle relative to the central axis of the superabrasive element.The assembly may further include a binding member interference fittedwith the outer surface of the at least one sidewall. The binding membermay compress the inner surface against the selected portion of thesuperabrasive element.

In an embodiment, a method of processing a superabrasive elementincludes overmolding a protective mask onto a selected portion of asuperabrasive element having a superabrasive table. The method mayfurther include exposing at least a portion of the superabrasive elementto a leaching agent such that the leaching agent contacts an exposedsurface region of the superabrasive table and at least a portion of theprotective mask. In an embodiment, the method further includesinterference fitting a binding member with an outer side surface of theovermolded protective mask near the superabrasive table.

Features from any of the disclosed embodiments may be used incombination with one another, without limitation. In addition, otherfeatures and advantages of the present disclosure will become apparentto those of ordinary skill in the art through consideration of thefollowing detailed description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate several embodiments, wherein identical referencenumerals refer to identical or similar elements or features in differentviews or embodiments shown in the drawings.

FIG. 1A is an isometric view of a superabrasive element according to anembodiment;

FIG. 1B is a cross-sectional view of the superabrasive elementillustrated in FIG. 1A;

FIG. 2A is an isometric view of an overmolded protective leaching maskassembly according to an embodiment;

FIG. 2B is a top view of the overmolded protective leaching maskassembly shown in FIG. 2A;

FIG. 2C is a cross-sectional view of the overmolded protective leachingmask assembly shown in FIG. 2B taken along section line 2C-2C;

FIG. 2D is a cross-sectional view of an overmolded protective leachingmask assembly according to another embodiment;

FIG. 3A is a cross-sectional view of the overmolded protective leachingmask assembly shown in FIG. 2C according to another embodiment;

FIG. 3B is a detailed cross-sectional view of the overmolded protectiveleaching mask assembly shown in FIG. 3A;

FIG. 4A is an isometric view of an overmolded protective leaching maskassembly according to another embodiment;

FIG. 4B is a cross-sectional view of the overmolded protective leachingmask assembly shown in FIG. 4A taken along section line 4B-4B.

FIG. 5A is a cross-sectional view of an injection mold press having aninjection system and clamping system for injection molding any of theovermolded protective masks disclosed herein;

FIG. 5B is a cross-sectional view of the injection mold assembly shownin FIG. 5A;

FIG. 5C is a cross-sectional view of an injection mold assemblyaccording to another embodiment;

FIG. 6A is an isometric view of an overmolded protective leaching maskassembly according to another embodiment;

FIG. 6B is a cross-sectional view of the overmolded protective leachingmask assembly shown in FIG. 6A taken along section line 6B-6B;

FIG. 6C is a cross-sectional view of the overmolded protective leachingmask assembly shown in FIG. 6A according to another embodiment.

FIG. 6D is a cross-sectional view of the overmolded protective leachingmask assembly shown in FIG. 6A according to another embodiment

FIG. 7A through 7C illustrate a method for mounting a binding memberonto an overmolded protective leaching mask according to an embodiment;

FIG. 8 is a flow diagram of a method of processing a polycrystallinediamond element according to an embodiment.

FIG. 9 is an isometric view of a drill bit according an embodiment,which includes one or more superabrasive cutting elements processedusing any of the leaching mask assemblies disclosed herein;

FIG. 10 is a partial cutaway isometric view of a thrust-bearingapparatus according to an embodiment, which includes one or more bearingelements processed using any of the leaching mask assemblies disclosedherein; and

FIG. 11 is a partial cutaway isometric view of a radial bearingapparatus according to an embodiment, which includes one or more bearingelements processed using any of the leaching mask assemblies disclosedherein.

DETAILED DESCRIPTION

Embodiments of the invention relate generally to overmolded protectiveleaching masks, and methods of manufacturing and using the same forleaching superabrasive elements such as polycrystalline diamondelements. Such polycrystalline diamond elements may be used as cuttingelements for use in a variety of applications, such as drilling tools,machining equipment, cutting tools, and other apparatuses, withoutlimitation. Polycrystalline diamond elements, as disclosed herein, mayalso be used as bearing elements in a variety bearing applications, suchas thrust bearings, radial bearing, and other bearing apparatuses,without limitation.

The terms “superabrasive” and “superhard,” as used herein, may refer toany material having a hardness that is at least equal to a hardness oftungsten carbide. For example, a superabrasive article may represent anarticle of manufacture, at least a portion of which may exhibit ahardness that is equal to or greater than the hardness of tungstencarbide. The term “cutting,” as used herein, may refer to machiningprocesses, drilling processes, boring processes, combinations thereof,or any other material removal process utilizing a cutting element and/orother cutting apparatus, without limitation.

FIGS. 1A and 1B illustrate a superabrasive element 10 according to anembodiment. As illustrated in FIGS. 1A and 1B, superabrasive element 10may include a superabrasive table 12 affixed to or formed upon asubstrate 14. Superabrasive table 12 may be affixed to substrate 14 atinterface 16. Superabrasive element 10 may include a rear face 18, asuperabrasive face 20, and an element side surface 22. In an embodiment,element side surface 22 may include a substrate side surface 24 formedby substrate 14 and a superabrasive side surface 26 formed bysuperabrasive table 12. Rear face 18 may be formed by substrate 14.Superabrasive element 10 may also include a superabrasive face 20.Optionally, superabrasive element 10 may include a chamfer 28 formed bysuperabrasive table 12. Chamfer 28 may include an angular and/or roundededge formed at the intersection of superabrasive side surface 26 andsuperabrasive face 20. In various embodiments, chamfer 28 may include achamfered surface and/or other selected geometry (e.g., one or moreradius and/or one or more chamfer, etc.) extending between superabrasiveside surface 26 and superabrasive face 20. At least one edge may beformed at the intersection of chamfer 28 and superabrasive face 20and/or at the intersection of chamfer 28 and superabrasive side surface26.

Superabrasive element 10 may include any suitable size, shape, geometry,or combinations thereof, without limitation. For example, superabrasiveelement 10 may exhibit a symmetrical shape or a non-symmetrical shape.In an embodiment, at least a portion of superabrasive element 10 mayhave a substantially cylindrical shape centered about a central axis 30.For example, superabrasive element 10 may include a substantiallycylindrical outer surface extending about the central axis 30 thatextends through superabrasive element 10, as illustrated in FIGS. 1A and1B. In an embodiment, one or more portions of element side surface 22may define at least part of a substantially cylindrical surface and mayhave any suitable diameter relative to central axis 28, withoutlimitation. In an embodiment, substrate side surface 24 andsuperabrasive side surface 26 may have substantially the same outerdiameter OD₁ relative to central axis 30, as shown in FIG. 1B. In otherembodiments, element side substrate side surface 24 and superabrasiveside surface 26 may each have a different outer diameter relative tocentral axis 30.

Substrate 14 may include any suitable material on which superabrasivetable 12 may be formed. For example, substrate 14 may include a cementedcarbide material, such as a cobalt-cemented tungsten carbide materialand/or any other suitable material. Substrate 14 may include a suitablemetal-solvent catalyst material, such as cobalt, nickel, iron, or alloysthereof. Substrate 14 may also include any other suitable materialincluding, without limitation, cemented carbides such as titaniumcarbide, niobium carbide, tantalum carbide, vanadium carbide, chromiumcarbide, and/or combinations of any of the preceding carbides cementedwith iron, nickel, cobalt, or alloys thereof. Superabrasive table 12 maybe formed of any suitable superabrasive and/or superhard material orcombination of materials, including, for example, PCD. In otherembodiments, superabrasive table 12 may include cubic boron nitride,silicon carbide, diamond, mixtures thereof, or composites including oneor more of the foregoing materials, without limitation.

Superabrasive table 12 may be formed using any suitable technique. Forexample, superabrasive table 12 may include a PCD layer formed bysubjecting a plurality of diamond particles (e.g., diamond particleshaving an average particle size between approximately 0.5 μm andapproximately 150 μm) to an HPHT sintering process in the presence of ametal-solvent catalyst, such as cobalt, nickel, iron, combinationsthereof, alloys thereof, or any other suitable group VIII element oralloys thereof. During an HPHT sintering process, adjacent diamondcrystals in a mass of diamond particles may become bonded to oneanother, forming a PCD table comprising directly bonded diamond crystalsexhibiting diamond-to-diamond bonding therebetween (e.g., sp³ bonding).In an embodiment, bonded diamond crystals in superabrasive table 12 mayhave an average grain size of approximately 20 μm or less. Further,during an HPHT sintering process, diamond grains may become bonded toadjacent to substrate 14 at interface 16.

According to various embodiments, superabrasive table 12 may be formedby placing diamond particles adjacent to substrate 14 includingcobalt-cemented tungsten carbide. In some embodiments, materialcomponents of substrate 14 may migrate into the interstitial regions inthe mass of diamond particles used to form superabrasive table 12 duringHPHT sintering. The resulting sintered PCD material formingsuperabrasive table 12 may include a matrix of bonded diamond grains andinterstitial regions defined between the bonded diamond grains. Suchinterstitial regions may be at least partially filled with variousmaterials, including, for example, cobalt, tungsten, tungsten carbide,or combinations of the foregoing.

According to an embodiment, as the mass of diamond particles issintered, a metal-solvent catalyst may melt and flow from substrate 14into the mass of diamond particles. As the metal-solvent flows intosuperabrasive table 12, it may also dissolve and/or carry additionalmaterials, such as tungsten and/or tungsten carbide, from substrate 14into the mass of diamond particles. As the metal-solvent catalyst flowsinto the mass of diamond particles, the metal-solvent catalyst, and anydissolved and/or undissolved materials may at least partially fillspaces between the diamond particles. The metal-solvent catalyst mayfacilitate bonding of adjacent diamond particles to form a PCD layer.Additionally, as the PCD layer is cooled, the metal-solvent catalyst maysolidify and adhere to diamond grains in the PCD layer, holding at leasta portion of the PCD layer in a compressed state.

Following sintering, various materials, such as a metal-solventcatalyst, remaining in interstitial regions within superabrasive table12 may reduce the thermal stability of superabrasive table 12 atelevated temperatures. It is currently believed that differences inthermal expansion coefficients between diamond grains in superabrasivetable 12 and a metal-solvent catalyst in interstitial regions betweenthe diamond grains may damage portions of superabrasive table 12 thatare exposed to elevated temperatures, such as temperatures developedduring drilling and/or cutting operations. Such portions ofsuperabrasive table 12 may be excessively worn and/or damaged during thedrilling and/or cutting operations.

Removing the metal-solvent catalyst and/or other materials fromsuperabrasive table 12 may improve its wear resistance, heat resistance,thermal stability, or combinations thereof, particularly in situationswhere the PCD material may be exposed to elevated temperatures. Ametal-solvent catalyst and/or other materials may be removed fromsuperabrasive table 12 using any suitable technique, including, forexample, leaching. In an embodiment, a metal-solvent catalyst, such ascobalt, may be removed from regions of superabrasive table 12, such asregions generally adjacent to the working surfaces of superabrasivetable 12. Removing a metal-solvent catalyst from superabrasive table 12may reduce damage to the PCD material caused by expansion of themetal-solvent catalyst.

At least a portion of a metal-solvent catalyst, such as cobalt, as wellas other materials, may be removed from at least a portion ofsuperabrasive table 12 using any suitable technique, without limitation.For example, chemical, liquid, gaseous leaching, or combinations thereofmay be used to remove a metal-solvent catalyst from superabrasive table12 up to a desired depth from a surface of superabrasive table 12. Forexample, the metal-solvent catalyst may be at least partially leachedfrom superabrasive table 12 to a selected depth “d” as measured from atleast one of superabrasive face 20, superabrasive side surface 26, orchamfer 28 to form a leached region that is at least partially depletedof the metal-solvent catalyst. For example, the leached region maygenerally contour superabrasive face 20, superabrasive side surface 26,and chamfer 28. The leached region may also extend along a selectedlength of superabrasive side surface 26. Generally, the selected depth“d” may be less than about 100 μm, greater than 250 μm, about 200 μm toabout 600 μm, greater than 300 μm to about 425 μm, greater than 350 μmto about 400 μm, greater than 350 μm to about 375 μm, about 375 μm toabout 400 μm, about 500 μm to about 650 μm, about 400 μm to about 600μm, about 600 μm to about 800 μm, or about 10 μm to about 500 μm.

Any suitable leaching agent, such as a leaching solution and/or a gasmixture, may be used to leach materials from superabrasive table 12,without limitation. For example, a corrosive leaching solution may beused to remove a metal-solvent catalyst from the interstitial spacesbetween diamond grains in superabrasive table 12. In some embodiments,the leaching solution may include various acids or bases, and/or othersuitable reagents, including, without limitation, peroxide, nitric acid,hydrofluoric acid, hydrochloric acid, mixtures thereof, or combinationsthereof. Superabrasive element 10 may be exposed to the leachingsolution for any suitable period of time. In some embodiments, onlyselected portions of superabrasive table 12 may be leached, leavingremaining portions unleached. For example, some portions of one or moresurfaces of superabrasive table 12 may be masked or otherwise protectedfrom exposure to a leaching solution and/or gas mixture, for example, bya protective mask 232 (shown in FIG. 2A), while other portions of one ormore surfaces of superabrasive table 12 may be exposed to the leachingsolution and/or gas mixture. Other suitable techniques may be used forremoving a metal-solvent catalyst and/or other materials fromsuperabrasive table 12 or may be used to accelerate a chemical leachingprocess. For example, exposing the superabrasive material to heat,pressure, electric current, microwave radiation, and/or ultrasound maybe employed to leach or to accelerate a chemical leaching process,without limitation. Following leaching, superabrasive table 12 mayinclude a volume of superabrasive table 12 that is substantially free ofa metal-solvent catalyst.

FIGS. 2A through 2C illustrate a protective leaching mask assembly 200according to an embodiment for selectively exposing the superabrasiveelement 10 to a leaching solution. The protective leaching mask assembly200 may include superabrasive element 10 and an overmolded protectivemask 232 at least partially surrounding superabrasive element 10.Protective mask 232 may help prevent leaching to superabrasive element10 when superabrasive element 10 is exposed to various leaching agents.For example, protective mask may help prevent a leaching solution fromchemically leaching certain portions of superabrasive element 10, suchas portions of substrate 14, portions of superabrasive table 12, orboth.

In some embodiments, portions of superabrasive element 10 that areaffixed and/or adjacent to protective mask 232 may be protected fromleaching, corrosion, and/or other damage under different leachingconditions, including, for example, temperatures ranging between abouttwenty-five (25) degrees Celsius and about four-hundred (400) degreesCelsius and pressures ranging between about one (1) bar and abouttwo-hundred (200) bar. In an embodiment, protective mask 232 may alsoenable leaching of superabrasive element 10 at temperatures below abouttwenty-five (25) degrees Celsius or above about four-hundred (400)degrees and/or at pressures below one (1) bar and/or above aboutone-hundred (100) bar.

Protective mask 232 may include any suitable material. Protective mask232 may include one or more materials that is configured to be directlyand/or indirectly overmolded on at least a portion of superabrasiveelement 10. For example, at least a portion of protective mask 232 maybe affixed and/or bonded to surface portions of substrate 14 and/orsuperabrasive table 14 such that a leaching solution is prevented orinhibited from passing between protective mask 232 and superabrasiveelement 10. In an embodiment, to help bond protective mask 232 tosuperabrasive element 10, protective mask 232 may include one or morematerials capable of bonding or affixing to superabrasive element 10under various conditions. In an embodiment, protective mask 232 mayinclude one or more materials capable of substantially maintaining itsshape and/or configuration during leaching of superabrasive element 10.In addition, protective mask 232 may include relatively stiffermaterials than conventional protective cups because the superabrasiveelement 10 need not be loaded into protective mask 232 like conventionalleaching cups. Protective mask 232 may include one or more materialssubstantially resistant to various chemicals present in a leachingsolution. For example, protective mask 232 may include one or morematerials that are substantially inert and/or otherwise resistant toacids, bases, and/or other reactive compounds present in a leachingsolution used to leach superabrasive element 10.

Protective mask 232 may also include one or more materials substantiallyresistant to expansion and/or shrinkage under conditions present duringleaching. For example, protective mask 232 may include one or morematerials exhibiting stability at various temperatures and/or pressures,including elevated temperatures and/or pressures used in leaching and/orotherwise processing superabrasive element 10.

In an embodiment, protective mask 232 may include one or more polymericmaterials. For example, protective mask 232 may include one or morethermoplastic polymer materials, including, without limitation, afluoropolymer, polypropylene, polyvinylidene fluoride, polyvinylchloride, polytetrafluoroethylene, polyvinylidene difluoride, orcombinations of the foregoing. In some embodiments, protective mask 232may include a material configured to contract against a selected portionof superabrasive element 10. As disclosed in co-pending application Ser.No. 12/555,715, protective mask 232 may include a thermosetting and/orthermoplastic material that may be formed over superabrasive element 10through the application of heat and/or pressure.

In an embodiment, protective mask 232 may include multiple layers ofmaterials. In an embodiment, the multiple layers of materials mayinclude one or more materials. For example, various layers of materialin protective mask 232 may include different materials. In anembodiment, the multiple layers of protective mask 232 may be formed atdifferent times. For example, a first layer may be overmolded directlyon at least a portion of substrate 14 and/or superabrasive table 12.Subsequently, a second layer may be overmolded on the first layer. In anembodiment, the first layer and second layer may be formed ofsubstantially the same materials. In other embodiments, the first layerand the second layer may be formed of different materials. In yet otherembodiments, additional layers formed of relatively the same and/ordifferent materials as the first layer and the second layer may also beformed.

Protective mask 232 may be selectively overmolded on portions ofsubstrate 14 and/or superabrasive table 12 in any suitable pattern,design, or as otherwise desired without limitation. According to someembodiments, protective mask 232 may be formed over a selected portionof superabrasive element 10 such that a surface region (e.g.superabrasive face 20) of superabrasive element 10 is exposed. Forexample, protective mask 232 may be overmolded on a selected portion ofsuperabrasive element 10 that includes at least a portion of substrate14 and/or superabrasive table 12.

As illustrated in FIG. 2C, protective mask 232 may be formed over aselected portion of superabrasive element 10 that includes rear face 18and substrate side surface 24, thereby inhibiting or preventing damageof substrate 14 during leaching. As further shown in FIG. 2C, protectivemask 232 may be overmolded onto at least a portion of superabrasiveelement 10 including the substrate side surface 24 and the superabrasiveside surface 26 between the lower edge of chamfer 28 and interface 16.

Referring to FIGS. 3A and 3B, according to another embodiment, chamfer28 may be omitted and the protective mask 232 may be overmolded onto atleast a portion of the superabrasive element 10 including the substrateside surface 24 and the superabrasive side surface 26 near thesuperabrasive face 20. In yet other embodiments, the protective mask 232may be overmolded onto at least a portion of the superabrasive element10 including the substrate side surface 24 near interface 16.

During leaching, a region of superabrasive element 10 that is notcovered by protective mask 232 may be exposed to a leaching solutionduring leaching. Additionally, the leaching solution may be inhibited orprevented from contacting a region which is covered by protective mask232. Accordingly, the leaching solution may be inhibited or preventedfrom dissolving, corroding, and/or otherwise damaging portions ofsuperabrasive element 10 at and/or near a selected portion on whichprotective mask 232 is overmolded. In an embodiment, the leachingsolution may also be inhibited or prevented from migrating betweensuperabrasive element 10 and protective mask 232, further protectingportions of superabrasive element 10 at and/or adjacent to the selectedportions.

In an embodiment, protective mask 232 may be bonded and/or otherwiseaffixed to superabrasive element 10 in any suitable manner. For example,protective mask 232 may be bonded to one or more portions of elementside surface 22 via one or more mechanical bonds, one or more chemicalbonds, combinations thereof, or any other suitable type of bond. Byovermolding protective mask 232 on superabrasive element 10, protectivemask 232 may be configured to provide a higher level of bonding betweensuperabrasive element 10 and protective mask 232 in comparison to aconventional protective leaching cup. In other embodiments, protectivemask 232 may be adhered to one or more of element side surface 22 using,for example, an adhesive. In an embodiment, protective mask 232 may beat least partially bonded to one or more portions of element sidesurface 22 through ionic bonds, covalent bonds, and/or variousintermolecular bonds.

In other embodiments, protective mask 232 may be overmolded onsuperabrasive element 10 such that mechanically and/or frictionallyengages one or more portions of element side surface 22. For example, asprotective mask 232 hardens during the molding process, protective mask232 may shrink and/or contract, causing protective mask 232 to moreclosely surround superabrasive element 10, mechanically affixingprotective mask 232 to superabrasive element 10. In other embodiments,one or portions of sidewalls 236 of protective mask 232 may beconfigured to at least partially conform to projections, cavities,indentations, and/or other surface irregularities defined by elementside surface 22. By at least partially conforming to surfaceirregularities defined by element side surface 22, protective mask 232may be more securely affixed or bonded to at least a portion ofsubstrate 12 and/or superabrasive table 14. For example, one or moregrooves 248 may be ground, cut, lapped, or otherwise formed in elementside surface 22 as shown in FIG. 3B. Accordingly, one or more portionsof protective mask 232 may be disposed between adjacent portions ofsubstrate 14 and/or superabrasive table 12. For example, portions ofprotective mask 232 may at least partially fill the grooves 248 asprotective mask 232 is overmolded onto superabrasive element 10.Accordingly, the interface between protective mask 232 and element sidesurface 22 may include alternating intermeshed portions of protectivemask 232 and element side surface 22. The alternating and/orintermeshing portions of protective mask 232 and element side surface 22may help mechanically fasten and hold protective mask 232 tosuperabrasive element 10.

The geometry of one or more portions of protective mask 232 may beselected to help protective mask 232 protect superabrasive element 10during leaching. As shown in FIGS. 2A and 2C, protective mask 232 mayinclude a base portion 234 and at least one sidewall 236 extending frombase portion 234 and defining an opening generally opposite the baseportion 234. Sidewall 236 of protective mask 232 may include the innerside surface 240, an outer side surface 246, and a thickness T definedbetween an inner surface (e.g., the inner side surface 240) and an outersurface (e.g., the outer side surface 246). As shown, in an embodiment,inner side surface 240 may be nonparallel relative to outer side surface246 of sidewall 236 and substantially parallel relative to one or moreportions of element side surface 22. The relationship between the innerside surface 240 and element side surface 22 may be configured toprovide a substantially close fit between protective mask 232 andsuperabrasive element 10. As discussed in more detail below, therelationship between inner side surface 240 and outer side surface 246may help eject protective leaching mask assembly 200 from an injectionmold.

Protective mask 232 may be formed to any suitable thickness. Forexample, the thickness of protective mask 232 may be configured to helpprevent a leaching solution from coming into contact with selectportions of superabrasive element 10. In some embodiments, a portion ofsidewall 236 nearer superabrasive table 12 may have a thickness T thatis greater than a thickness T of a portion of sidewall 236 nearer rearface 18. The increased thickness T of protective mask 232 nearsuperabrasive table 12 may help protect substrate 14 from pitting andother corrosion due to exposure to a leaching solution. In otherembodiments, protective mask 232 may also be formed to exhibit athickness that facilitates suitable bonding and/or adhesion ofprotective mask 232 to portions of superabrasive element 10. Forexample, in an embodiment, base portion 234 and sidewall 236 ofprotective mask 232 may exhibit a thickness T of less than about 0.1inches. In an embodiment, one or more portions of sidewall 236 mayexhibit a thickness T of less than about 0.5 inches. In otherembodiments, one or more portions of sidewall 236 may exhibit athickness T of between about 0.03 inches and about 0.25 inches. In yetother embodiments, one or more portions of sidewall 236 may exhibit athickness T of between about 0.05 inches and about 0.15 inches. In otherembodiments, one or more portions of sidewall 236 may exhibit a largeror smaller thickness T. Moreover, protective mask 232 may exhibit arelatively uniform thickness or a varying thickness. In otherembodiments, one or more portions of sidewall 236 and/or base portion234 may have different diameters and/or shapes. For example, a portionof sidewall 236 proximate to superabrasive table 12 may have a differentdiameter and/or shape than a portion of sidewall 236 nearer rear face18.

In other embodiments, one or more portions of protective mask 232 mayexhibit a draft or taper configured to help improve performance ofprotective leaching mask assembly 200. For example, upper portion ofprotective mask 232 may exhibit an outer diameter OD_(P1) (shown in FIG.3A) that is wider than an outer diameter OD_(P2) (shown in FIG. 3A) ofbase portion 234 of protective mask 232 such that one or more portionsof outer side surface 246 of sidewall 236 exhibit a draft or taperbetween base portion 234 and the opening. As shown, the outer diameterof protective mask 232 may increase from base portion 234 toward upperportion of protective mask 232 forming a draft or taper. In otherembodiments, the outer diameter of protective mask 232 may increase fromupper portion of protective mask 232 toward base portion 234 forming adraft or taper. For example, FIG. 2D illustrates a protective leachingmask assembly 200′ according to another embodiment. As shown in FIG. 2D,upper portion of protective mask 232′ may exhibit an outer diameterOD_(P1) that is less than an outer diameter OD_(P2) of base portion 234′of protective mask 232′ such that the outer diameter of protective mask232′ increases from upper portion of protective mask 232′ toward baseportion 234′ forming a draft or taper with sidewall 236′.

Referring again to FIG. 2C, the draft of sidewall 236 may form a draftangle θ between a line extending along sidewall 236 and another lineextending at a right angle relative to an inner lower surface of baseportion 234 such as a central axis of the superabrasive element 10. Inan embodiment, the draft angle θ of sidewall 236 may be selected toallow for easier ejection of protective mask 232 from an injection mold.For example, one or more portions of outer side surface 246 may beconfigured to exhibit a draft angle θ of greater than about one-fourth(¼) degree. In other embodiments, one or more portions of outer sidesurface 246 may be configured to exhibit a draft angle θ of betweenabout one-fourth (¼) degree and about seven (7) degrees; about half (½)degree and about three (2) degrees; about two (2) degrees and about four(4) degrees; about four (4) degrees and about six (6) degrees; or aboutone (1) degree and about two (2) degrees. In other embodiments, one ormore portions of outer side surface 246 may exhibit a greater or lesserdraft angle θ. Such a configuration may help facilitate loading orpositioning of a binding member (e.g., binding member 250) ontoprotective mask 232. In addition, the draft or taper of sidewall 236 mayhelp vary the thickness T of sidewall 236. Such a configuration may alsohelp release protective leaching mask assembly 200 from a mold cavityupon overmolding of protective mask 232 on superabrasive element 10. Insome embodiments, protective mask 232 may include one or more radii 262.For example, protective mask 232 may include one or more radii 262extending between sidewall 236 and base portion 234. Such aconfiguration may help reduce failure of protective mask 232, stressconcentrations, and/or poor flow patterns during the overmold process.

Protective mask 232 may be substantially removed from superabrasiveelement 10 using any suitable technique, including, for example,machining, lapping, grinding, crushing, breaking, grit-blasting,chemical treatments, combinations of the foregoing, or otherwisephysically and/or chemically removing protective mask 232 fromsuperabrasive element 10.

It is contemplated herein that the protective leaching mask assembliesdisclosed herein may exhibit any suitable, size, shape, geometry, orcombinations thereof, without limitation. For example, in an embodiment,a protective leaching mask assembly may be non-cylindrical. FIGS. 4A and4B illustrate a protective leaching mask assembly 400 similar toprotective leaching mask assembly 200, except that protective leachingmask assembly 400 includes a protective mask 432 overmolded on asuperabrasive element 410 having a substantially rounded rectangularshape. As shown, superabrasive element 410 may include a superabrasivetable 412 affixed to or formed upon a substrate 414. Superabrasiveelement 410 may include a rear face 418, a superabrasive face 420, achamfer 428 formed by superabrasive table 412, and an element sidesurface 422. Superabrasive element 410 may exhibit a generally roundedrectangular shape.

Protective mask 432 may include a base portion 434 and at least onesidewall 436 extending from base portion 434 defining an openinggenerally opposite the base portion 434. Protective mask 432 may beselectively overmolded on one or more portions of superabrasive element410 in any pattern, design, or as otherwise desired, without limitation.When superabrasive element 410 is exposed to a leaching solution,protective mask 432 may be configured to substantially cover and/or bondto one or more portions of superabrasive element 410 in order to helpprevent leaching solution or other liquids from contacting and/ordamaging the one or more portions of element side surface 422 (e.g., asubstrate side surface) and rear face 418. Similar to protective mask232, protective mask 432 may be bonded, affixed, and/or otherwiseadhered to superabrasive element 410 in any suitable manner. Forexample, protective mask 432 may be bonded to one or more portions ofelement side surface 422 via one or more mechanical bonds, one or morechemical bonds, combinations thereof, or any other suitable bond type.Moreover, like protective mask 232, protective mask 432 may include anysuitable material. For example, protective mask 432 may include one ormore materials that are substantially inert and/or otherwise resistantto acids, bases, and/or other reactive compounds present in a leachingsolution used to leach superabrasive element 410. In an embodiment,protective mask 432 may include one or more thermoplastic polymermaterials, including, without limitation, a fluoropolymer,polypropylene, polyvinylidene fluoride, polyvinyl chloride,polytetrafluoroethylene, polyvinylidene difluoride, or combinations ofthe foregoing.

As disclosed in co-pending application Ser. No. 12/555,715, protectivemasks described herein may be overmolded on the superabrasive elementsin any suitable manner. For example, without limitation, via injectionmolding, insert molding, multiple material molding, thin wall injectionmolding, gas-assist molding, injection compression molding, or any othersuitable molding technique may be utilized for overmolding a protectivemask on superabrasive elements. FIG. 5A is a side cross-sectional viewof an embodiment injection molding press 50 that may be utilized tomanufacture any of the protective leaching mask assemblies disclosedherein. The injection mold press 50 is an example of suitable injectionmolding equipment and techniques, although the particular configurationor operation of the injection molding press 50 may vary in some regardswith respect to other machines or processes. In the illustratedembodiment, injection molding press 50 includes a material hopper 52, aninjection system 54, and a clamping system 56. In an embodiment,materials or material pellets may be placed within the material hopper52, and gravity fed or force fed into the injection system 54. In anembodiment, the materials or material pellets may include any suitablematerials. For example, the material pellets may include one or morethermoplastic polymer materials, including, without limitation, afluoropolymer, polypropylene, polyvinylidene fluoride, polyvinylchloride, polytetrafluoroehtylene, polyvinylidene difluoride, orcombinations thereof.

The injection system 54 may include a reciprocating screw 58 thatrotates within a barrel 60. A heater 62 may surround the barrel 60 orotherwise operate to at least partially or completely melt the receivedpellets. The melted material is conveyed by the reciprocating screw 58towards the clamping system 56. The clamping system 56 includes a mold64 having two plates 64A, 64B. A stationary plate 64A remains in agenerally fixed position, while a moving plate 64B is connected to amoveable platen 66. The moveable platen 66 may be selectively moved. Asthe moveable platen 66 moves, the moving plate 64B also moves in acorresponding direction, which may open or close the mold 64 based onthe travel direction. The stationary and moving plates 64A, 64Bcollectively define a mold cavity 68 and, when the mold 64 is in aclosed position, the mold cavity 68 is closed between the two plates64A, 64B. As shown in FIG. 5B, vents 72 may be formed between thestationary and moving plates 64A, 64B. The vents may be sized andconfigured to allow air and other gases in the mold cavity 68 to leavethe injection molding press 50 as a melted material flows into the moldcavity 68. Such a configuration may allow for greater injection rates, amore uniform protective mask, and increased strength in the protectivemasks.

The injection system 54, which is operably coupled to the materialhopper 52 and the mold 64, is configured to receive the material pelletsfrom the material hopper 52 and convey the melted materials into themold cavity 68. In an embodiment, the superabrasive element 10 may beselectively positioned in the mold cavity 68 with the mold 64 in an openposition. The moveable platen 66 may then be moved to move the mold 64in the closed or clamped position. With the mold 64 in the closedposition, molten material (e.g., polypropylene) may be forced by thereciprocating screw 58 through a nozzle 70 and into the cavity 68 ontoone or more selected portions of the superabrasive element 10. Theinjected material may then be allowed to cool forming a protectiveleaching mask assembly 11 including a protective mask 232 formed on thesuperabrasive element 10. As the injected material cools, the injectedmaterial may bond and/or otherwise affix to the superabrasive element10. After cooling, the mold 64 is opened, and ejector pins may be usedto extract the protective leaching mask assembly 11 from the mold 64. Insome embodiments, additional shots of injected material may be forcedthrough the nozzle 70 to form one or more additional layers of theprotective mask 232 before protective leaching mask assembly 11 isejected from the mold 64.

As discussed above, sidewalls of the mold cavity 68 may be sloped suchthat the sidewalls of the protective mask 232 exhibit a draft or taper.Such a configuration may allow for easier ejection of the protectiveleaching mask assembly 11 from the mold 64. In addition, the presence ofradii in the corners of the mold cavity 68 may help reduce localizedstresses in the protective mask 232.

FIG. 5C illustrates a mold 64′ according to another embodiment. Mold 64′may include two plates 64A′, 64B′. A stationary plate 64A′ remains in agenerally fixed position, while a moving plate 64B′ is connected to themoveable platen 66 (shown in FIG. 5A) and is moveable. An insert 65′ maybe removably positioned in the stationary plate 64A′. In an embodiment,insert 65′ may comprise a single member. In other embodiments, insert65′ may comprise two, three, or any other suitable number of members.The stationary plate 64A′, the moving plate 64B′ and the insert 65′ maycollectively define a mold cavity 68′ and, when the mold 64′ is in aclosed position, the mold cavity 68′ is closed between the two plates64A′, 64B′ and insert 65′. Like mold 64, vents 72′ may be formed betweenthe stationary and moving plates 64A′, 64B′. With the mold 64′ in theclosed position, molten material may be forced into the cavity 68′ ontoone or more selected portions of the superabrasive element 10. Theinjected material may then be allowed to cool forming the protectivemask assembly 200′, including a protective mask 232′ formed on thesuperabrasive element 10.

As shown, insert 65′ may include an inner surface that is tapered orsloped such that the outer diameter of the protective mask 232′increases from the top edge toward the base portion forming a draft ortaper. In addition, insert 65′ may include an outer surface thatgenerally corresponds to the sidewalls of the stationary plate 64A′.Such a configuration may allow for easier ejection of the protectiveleaching mask assembly 200′ and insert 65′ from the mold 64′. Forexample, after cooling, the mold 64′ may be opened and ejector pins maybe used to extract the protective leaching mask assembly 200′ and insert65′ from the mold 64′. After removal from the mold 64′, the protectiveleaching mask assembly 200′ may be removed from the insert 65′.

In an embodiment, heat and/or pressure may be applied to a protectivemask to cause a portion of a protective mask abutting element sidesurface to more closely conform to one or more portions of element sidesurface of the superabrasive element. For example, referring to FIGS. 6Aand 6B, according to another embodiment, protective leaching maskassembly 200 (described in relation to FIGS. 1A through 3B) may furtherinclude a binding member 250 selectively positioned on protective mask232. Binding member 250 may be selectively positioned or loaded ontoprotective mask 232 to help prevent damage to superabrasive element 10during leaching. In an embodiment, binding member 250 may beinterference fit (e.g., press fit, shrink fit, combinations thereof,and/or otherwise loaded onto protective mask 232) in any suitablemanner. For example, binding member 250 may be sized and configured suchthat an interference fit is created between protective mask 232 andbinding member 250. In an embodiment, binding member 250 may exert acontact pressure on sidewall 236 that does not exceed a yield stress ofbinding member 250, sidewall 236, and or element side surface 22 suchthat binding member 250 creates an interference fit with select portionsof sidewall 236. Thus, binding member 250 may help the selected portionsof sidewall 236 more closely conform to element side surface 22. In anembodiment, an interference between binding member 250 and protectivemask 232 may be less than about 0.200 inches (e.g., about 0.100 inches),less than about 0.100 inches, less than about 0.080 inches, less thanabout 0.050 inches, less than about 0.040 inches (e.g., about 0.035inches), less than about 0.020 inches, or less than about 0.010 inches.In other embodiments, the interference between binding member 250 andprotective mask 232 may be between about 0.003 inches and about 0.030inches; between about 0.005 inches and about 0.020 inches; between about0.008 inches and about 0.016 inches; or between about 0.010 inches andabout 0.012 inches. In other embodiments, the interference between thebinding member 250 and protective mask 232 may be larger or smaller.Optionally, prior to loading binding member 250 onto protective mask232, binding member 250 and/or protective mask 232 may be heated to anelevated temperature to facilitate positioning of binding member 250about protective mask 232.

Binding member 250 may include any suitable material. For example,binding member 250 may include polytetrafluoroethylene (e.g., TEFLON®),polyphenylene, polypropylene, ultra-high-molecular weight polyethylene,metals, alloys, composite materials, combinations thereof, or any othersuitable type of material. In other embodiments, binding member 250 mayinclude one or more resilient materials. In yet other embodiments,binding member 250 may include one or more shape memory materials. In anembodiment, binding member 250 and protective mask 232 may includedifferent materials. In other embodiments, binding member 250 andprotective mask 232 may include the same materials. In an embodiment,binding member 250 may be configured to include one or more resilientmaterials configured to help binding member 250 apply a compressiveforce against protective mask 232.

In other embodiments, binding member 250 and protective mask 232 mayinclude one or more flexible and/or semi-flexible materials. In yetother embodiments, binding member 250 may be configured to exhibit aflexural modulus that exceeds a flexural modulus of protective mask 232.For example, the flexural modulus of binding member 250 may be at leastsix times (6) greater, or about at least three (3) times greater than aflexural modulus of one or more portions of protective mask 232. Inother embodiments, the flexural modulus of binding member 250 may bebetween about one (1) time and about eight (8) times, about two (2)times and about six (6) times, or about three (3) times and about five(5) times greater than protective mask 232. In other embodiments, thedifference between the flexural modulus of binding member 250 andprotective mask 232 may be greater or less. The difference between theflexural modulus of the binding member 250 and protective mask 232 mayallow binding member 250 to compress the protective mask 232 againstsuperabrasive element 10. Moreover, because of the compressive forceexerted by binding member 250 on protective mask 232, protectiveleaching mask assembly 200 may enable superabrasive element 10 to beexposed to a leaching agent without the use of a conventional leachingtray.

In other embodiments, protective mask 232 may be configured to exhibit aflexural modulus that exceeds a flexural modulus of binding member 250.For example, the flexural modulus of protective mask 232 may be at leastsix times (6) greater, or about at least three (3) times greater than aflexural modulus of binding member 250. In other embodiments, theflexural modulus of protective mask 232 may be between about one (1)time and about eight (8) times, about two (2) times and about six (6)times, or about three (3) times and about five (5) times greater thanbinding member 250. Such a configuration may help elastically loadbinding member 250 on protective mask 232.

Binding member 250 may be positioned on protective mask 232 in anysuitable manner. For example, binding member 250 may be selectivelypositioned or loaded onto a portion of outer surface 246 of sidewall 236extending between substrate side surface 24 near interface 16 andsuperabrasive side surface 26 near chamfer 28. In an embodiment, bindingmember 250 may be positioned about the periphery of a top edge ofprotective mask 232. In other embodiments, binding member 250 may beselectively positioned or loaded onto a portion of outer portion 246 ofsidewall 236 extending between interface 16 and chamfer 28, a portion ofouter portion 246 between substrate side surface 24 and interface 16, orin any other suitable location. In yet other embodiments, binding member250 may be selectively positioned and/or loaded onto protective mask 232such that binding member 250 overlaps more than half of sidewall 236.For example, as shown in FIG. 6C, binding member 250 may be selectivelypositioned or loaded onto a portion of outer portion 246 of sidewall 236extending between the top edge of protective mask 232 and a locationtoward rear face 18.

Referring again to FIG. 6B, in an embodiment, binding member 250 mayinclude a ring-like member defining an opening 252 through which atleast a portion of protective mask 232 may selectively extend. In anembodiment, binding member 250 may have an upper surface 258, a lowersurface 260, an inner surface 254 extending between upper surface 258and lower surface 260, and an outer surface 256 substantially parallelrelative to inner surface 254. In other embodiments, inner surface 254may be non-parallel relative to outer surface 256. Opening 252 may atleast partially define an inner diameter ID_(B) and outer surface 256may at least partially define an outer diameter OD_(B).

In an embodiment, outer diameter OD_(B) may be between about one-half(½) inch and about three (3) inches, about three quarters (¾) of an inchand about two (2) inches, or about one (1) inch and about one and a half(1½) inches. In other embodiments, outer diameter OD_(B) may be largeror smaller. Opening 252 may be configured to exhibit one or moregeometric shapes generally corresponding to a peripheral shape ofprotective mask 232. For example, opening 252 may exhibit a generallycylindrical shape. In other embodiments, opening 252 may exhibit agenerally conical shape, a generally rectangular shape, a generallyoval-like shape, or any other suitable shape. Moreover, while bindingmember 250 is illustrated exhibiting a generally ring-like shape, inother embodiments, binding member 250 may exhibit a generally torusshape, a generally frustoconical shape, a generally elliptical shape, orany other suitable shape. Optionally, binding member 250 may include oneor more features configured to help binding member 250 grip, interlockwith, or hold onto protective mask 232. For example, one or moreportions of inner surface 254 may include one or more adhesivesconfigured to help binding member 250 hold onto protective mask 232. Inother embodiments, one or more portions of inner surface 254 of bindingmember 250 may include a textured surface, an engagement feature, orother geometric feature configured to help binding member 250 gripprotective mask 232.

Binding member 250 may exhibit a thickness T_(B) at least partiallydefined between inner surface 254 and outer surface 256. In anembodiment, thickness T_(B) may be generally uniform. In otherembodiments, thickness T_(B) may be variable. In an embodiment,thickness T_(B) may be less than about one (1) inch, less than aboutone-half (½) inch, less than about three-eighths (⅜) of an inch, orgreater than about one-fourth (¼) of an inch. In other embodiments,thickness T_(B) may be between about one-fourth (¼) of an inch and abouttwo (2) inches, or about three-eighths (⅜) of an inch and about one (1)inch. In other embodiments, thickness T_(B) may be greater or less.

In an embodiment, binding member 250 may include one or more materialsincluding a selected elasticity such that binding member 250 elasticallydeforms as protective mask 232 and superabrasive element 10 are loadedinto binding member 250. As noted above, the size, shape, and/orconfiguration of opening 252 may be selected such that an interferencefit is created between protective mask 232 and binding member 250. Forexample, an interference between binding member 250 and protective mask232 may be less than about 0.200 inches (e.g., about 0.100 inches), lessthan about 0.100 inches, less than about 0.080 inches, less than about0.050 inches, less than about 0.040 inches (e.g., about 0.035 inches),less than about 0.020 inches, or less than about 0.010 inches.Accordingly, binding member 250 may help prevent leaching superabrasiveelement 10 by pushing sidewall 236 of protective mask 232 againstsuperabrasive element 10.

In an embodiment, protective mask 232 may include a binding memberloading portion configured to facilitate loading and/or positioning ofbinding member 250 on protective mask 232. For example, as shown in FIG.6D, a binding member engaging portion 247 may include a generallyconstant diameter portion of outer portion 246 located between the topedge of protective mask 232 and a location between substrate sidesurface 24 and interface 16. In an embodiment, binding member 250 may besized and configured to generally correspond to the binding memberloading portion 247 of protective mask 232. For example, the height ofbinding member 250 (e.g., distance between the upper and lower surfaces258, 260) may be substantially the same as the height of the bindingmember loading portion 247. Such a configuration may help concentrateand/or direct compressive forces exerted by binding member 250 on theprotective mask 232.

While binding member loading portion 247 is shown located between thetop edge and a location between substrate side surface 24 and interface16, in other embodiments, binding member loading portion 247 may belocated at any suitable location on outer portion 246 of protective mask232. For example, in an embodiment, binding member loading portion 247may be located below the top edge and between substrate side surface 24near interface 16 and superabrasive side surface 26 near chamfer 28.

FIGS. 7A through 7C illustrate a method 700 of mounting binding member250 onto protective mask 232 and superabrasive element 10 according toan embodiment. As shown in FIG. 7A, at step 702, binding member 250 maybe positioned on a press 760. Press 760 may include any suitable type ofpress including, without limitation, a hydraulic press, a mechanicalpress, or a pneumatic press. Press 760 may include a base member 764 anda ram member 762, which is mounted for reciprocation with respect tobase member 764. In an embodiment, base member 764 may include a recess766 configured to receive at least a portion of binding member 250 andan internal cavity 768 configured to receive at least a portion ofprotective mask 232 and superabrasive element 10. As shown, at least abottom portion of binding member 250 may be positioned in recess 766 ofbase member 764. Base portion of protective mask 232 and superabrasiveelement 10 may be positioned on an upper portion of binding member 250such that protective mask 232 and superabrasive element 10 arepositioned between ram member 762 and binding member 250.

At step 704, ram member 762 may be moved toward base member 764 suchthat at least a portion the protective mask 232 and superabrasiveelement 10 are press fit through opening 252 of binding member 250 andinto cavity of base member 764. In an embodiment, the draft or taper ofsidewall 236 of protective mask 232 may be configured to help loadprotective mask 232 into binding member 250 and/or protectivesuperabrasive element 10. For example, the diameter of an upperperipheral surface of protective mask 232 may be greater than thediameter ID_(B) of opening 252 of binding member 250. In addition, thediameter OD_(P2) (shown in FIG. 3A) of base portion 234 of protectivemask 232 may be less than the diameter of opening 252 of binding member250. As a result, base portion 242 of protective mask 232 may be moreeasily positioned within opening 252 prior to loading. In addition, asram member 762 pushes protective mask 232 further through opening 252 ofbinding member 250, the protective mask 232 becomes more wedged insideof opening 252. Thus, a greater compressive force against the protectivemask 232 is generated as the binding member 250 moves closer tosuperabrasive table 12 of superabrasive element 10. Such a configurationmay help protective mask 232 create a tighter fit with superabrasiveelement 10 to further prevent or inhibit a leaching solution frompassing between protective mask 232 and superabrasive element 10.

In other embodiments, movement of ram member 762 relative to base member764 may be controlled to selectively position binding member 250 onprotective mask 232 and superabrasive element 10. For example, rammember 762 may be moved a selected distance toward base member 764 suchthat binding member 250 is positioned over a portion of outer surface246 of sidewall 236 extending between substrate side surface 24 nearinterface 16 and superabrasive side surface 26 near chamfer 28. In anembodiment, ram member 762 may be moved a selected distance toward basemember 764 such that binding member 250 is positioned about theperiphery of a top edge of protective mask 232. In another embodiment,ram member 762 may be moved a selected distance toward base member 764such that binding member 250 is positioned over a portion of outersurface 246 of sidewall 236 extending between interface 16 and chamfer28, a portion of outer surface 246 between substrate side surface 24 andinterface 16, or in any other suitable location.

At step 706, ram member 762 may be reciprocated away from base member764 and protective mask 232 and binding member 250 may be removed frompress 760. While method 700 is illustrated using a press, it will beappreciated that binding member 250 may be loaded unto protective mask232 in any suitable manner. For example, binding member 250 may bemanually loaded onto protective mask 232. In other embodiments, bindingmember 250 may be shrink fitted onto protective mask 232. In yet otherembodiments, binding member 250 may be selectively tightened ontoprotective mask 232 using one or more mechanical fasteners.

FIG. 8 illustrates a method 800 of processing a superabrasive elementaccording to an embodiment. As shown in FIG. 8, at step 802, aprotective mask may be overmolded on a selected portion of superabrasiveelement (e.g., a polycrystalline element) including a superabrasivetable such that the protective mask is affixed and/or bonded to theselected portion of the superabrasive element. The protective mask maybe bonded and/or otherwise affixed to the superabrasive element in anysuitable manner disclosed herein. For example, the protective mask maybe bonded to one or more portions of the element side surface via one ormore mechanical bonds, one or more chemical bonds, combinations thereof,or any other suitable type of bond. Moreover, the protective mask mayinclude any suitable material, including, for example, withoutlimitation, one or more thermoplastic polymer materials, including,without limitation, a fluoropolymer, polypropylene, polyvinylidenefluoride, polyvinyl chloride, polytetrafluoroethylene, polyvinylidenedifluoride, or combinations of the foregoing. In an embodiment, at step804, a binding member may be loaded onto the protective mask to helpfurther bond or affix the protective mask to the selected portion of thesuperabrasive element.

At step 806, at least a portion of the superabrasive table may beexposed to a leaching solution such that the leaching solution contactsan exposed surface region of the superabrasive table and at least aportion of the protective mask. Because the protective mask is bondedand/or otherwise affixed to the selected portion of the superabrasiveelement, the protective mask may enable the superabrasive element to beexposed to a leaching solution for relatively longer periods of timeand/or to relatively stronger leaching solutions than conventionalmasking techniques. Additionally, the superabrasive element may beexposed to a leaching solution under conditions such as elevatedtemperatures and/or reduced pressures.

At step 808, the superabrasive element and protective mask may beremoved from the leaching solution. At step 810, the protective mask maybe substantially removed from the superabrasive table.

FIG. 9 is an isometric view of a drill bit 80 according to an embodimentthat may employ one or more superabrasive elements 10 processed usingany of the leaching mask assemblies disclosed herein. Drill bit 80 mayrepresent any type or form of earth-boring or drilling tool, including,for example, a rotary drill bit. As shown, drill bit 80 may include abit body 81 having a longitudinal axis 84. Bit body 81 may define aleading end structure for drilling into a subterranean formation byrotating bit body 81 about longitudinal axis 84 and applying weight tobit body 81. Bit body 81 may include radially and longitudinallyextending blades 79 with leading faces 82 and a threaded pin connection83 for connecting bit body 81 to a drill string.

At least one superabrasive element 10 may be attached to bit body 81.For example, a plurality of superabrasive elements 10 may be attached toblades 79. Drill bit 80 may utilize any of the disclosed superabrasiveelements 10 as cutting elements that have been leached using any of theprotective leaching mask assemblies or methods disclosed herein.Circumferentially adjacent blades 79 may define so-called junk slots 85therebetween. Junk slots 85 may be configured to channel debris, such asrock or formation cuttings, away from superabrasive elements 10 duringdrilling. Drill bit 80 may also include a plurality of nozzle cavities86 for communicating drilling fluid from the interior of drill bit 80 tosuperabrasive elements 10.

Drill bit 80 may additionally represent any number of earth-boring toolsor drilling tools, including, for example, core bits, roller-cone bits,fixed-cutter bits, eccentric bits, bicenter bits, reamers, reamer wings,and/or any other downreceptacle tools comprising superabrasive cuttingelements and/or discs, without limitation. Superabrasive elements 10disclosed herein may also be utilized in applications other than cuttingtechnology. For example, embodiments of superabrasive elements 10disclosed herein may also form all or part of heat sinks, wire dies,bearing elements, cutting elements, cutting inserts (e.g., on a rollercone type drill bit), machining inserts, or any other article ofmanufacture, as known in the art. According to some examples,superabrasive elements 10, as disclosed herein, may be employed inmedical device applications, including, without limitation, hip joints,back joints, or any other suitable medical joints. Thus, superabrasiveelements 10, as disclosed herein, may be employed in any suitablearticle of manufacture. Other examples of articles of manufacture thatmay incorporate superabrasive elements as disclosed herein may be foundin U.S. Pat. Nos. 4,811,801; 4,268,276; 4,468,138; 4,738,322; 4,913,247;5,016,718; 5,092,687; 5,120,327; 5,135,061; 5,154,245; 5,460,233;5,544,713; and 6,793,681, the disclosure of each of which isincorporated herein, in its entirety, by this reference.

In additional embodiments, a rotor and a stator, such as a rotor and astator used in a thrust-bearing apparatus, may each include at least onesuperabrasive element according to the methods or embodiments disclosedherein. By way of example, U.S. Pat. Nos. 4,410,054; 4,560,014;5,364,192; 5,368,398; and 5,480,233, the disclosure of each of which isincorporated herein, in its entirety, by this reference, disclosesubterranean drilling systems that include bearing apparatuses utilizingsuperabrasive elements 10 as disclosed herein.

FIG. 10 is partial cross-sectional isometric view of a thrust-bearingapparatus 87 according to an embodiment. Thrust-bearing apparatus 87 mayutilize any of the disclosed superabrasive elements 10 as bearingelements, which may have been leached using any of the protectiveleaching mask assemblies disclosed herein. Thrust-bearing apparatus 87may also include bearing assemblies 88A and 88B. Each of bearingassemblies 88A and 88B may include a support ring 89 fabricated from amaterial, such as steel, stainless steel, or any other suitablematerial, without limitation.

Each support ring 89 may include a plurality of recesses 90 configuredto receive corresponding superabrasive elements 10. Each superabrasiveelement 10 may be mounted to a corresponding support ring 89 within acorresponding recess 90 by brazing, welding, press-fitting, usingfasteners, or any another suitable mounting technique, withoutlimitation. In an embodiment, one or more of superabrasive elements 10may be configured according to any of the superabrasive elementembodiments or manufactured according to the methods described herein.For example, each superabrasive element 10 may include a substrate 14and a superabrasive table 12 comprising a PCD material. Eachsuperabrasive table 12 may form a superabrasive face 20 that is utilizedas a bearing surface.

Superabrasive faces 20 of bearing assembly 88A may bear against opposingsuperabrasive faces 20 of bearing assembly 88B in thrust-bearingapparatus 87. For example, bearing assembly 88A of thrust-bearingapparatus 87 may be termed a “rotor.” The rotor may be operably coupledto a rotational shaft. Bearing assembly 88B of thrust-bearing apparatus87 may be held substantially stationary relative to the bearing assembly88A and may be termed a “stator.”

FIG. 11 is an isometric view of a radial bearing apparatus 91 accordingto another embodiment. Radial bearing apparatus 91 may utilize any ofthe disclosed superabrasive element embodiments as bearing elements 10Aand 10B. Radial bearing apparatus 91 may include an inner race 92Apositioned generally within an outer race 92B. Inner race 92A mayinclude a plurality of bearing elements 10A affixed thereto, and outerrace 92B may include a plurality of corresponding bearing elements 10Baffixed thereto. One or more of bearing elements 10A and 10B may beconfigured in accordance with any of the superabrasive elementembodiments disclosed herein that may have been leached using any of theprotective leaching cups disclosed herein.

Inner race 92A may be positioned generally within outer race 92B. Thus,inner race 92A and outer race 92B may be configured such that bearingsurface 20A defined by bearing elements 10A and bearing surface 20Bdefined by bearing elements 10B may at least partially contact oneanother and move relative to one another as inner race 92A and outerrace 92B rotate relative to each other. According to variousembodiments, thrust-bearing apparatus 87 and/or radial bearing apparatus91 may be incorporated into a subterranean drilling system.

While various aspects and embodiments have been disclosed herein, otheraspects and embodiments are contemplated. The various aspects andembodiments disclosed herein are for purposes of illustration and arenot intended to be limiting. Additionally, the words “including,”“having,” and variants thereof (e.g., “includes” and “has”) as usedherein, including the claims, shall be open ended and have the samemeaning as the word “comprising” and variants thereof (e.g., “comprise”and “comprises”).

What is claimed is:
 1. A protective leaching mask assembly, comprising:a superabrasive element including a central axis and a superabrasivetable; a protective mask overmolded onto at least a portion of thesuperabrasive element, the protective mask including: a base portion;and at least one sidewall extending from the base portion and definingan opening generally opposite the base portion, the at least onesidewall including: an inner surface that abuts with a selected portionof the superabrasive element being chemically resistant to a leachingagent; and an outer surface sloping at an oblique angle relative to thecentral axis of the superabrasive element and non-parallel to the innersurface.
 2. The protective leaching mask assembly of claim 1, whereinthe at least one sidewall includes a thickness defined between the innersurface and the outer surface, and wherein the thickness is greaterproximate to the opening than the base portion of the protective mask.3. The protective leaching mask assembly of claim 1, wherein the innersurface of the protective mask is bonded to the selected portion of thesuperabrasive element via at least one of a mechanical bond or achemical bond.
 4. The protective leaching mask assembly of claim 1,wherein the superabrasive table includes a side surface, and wherein theselected portion includes at least a portion of the side surface of thesuperabrasive table.
 5. The protective leaching mask assembly of claim1, wherein the superabrasive element includes a substrate having asubstrate side surface and an upper surface bonded to the superabrasivetable, and wherein the selected portion includes at least a portion ofthe substrate side surface of the substrate.
 6. The protective leachingmask assembly of claim 1, wherein the protective mask includes at leastone of polypropylene, polyvinylidene fluoride, or a fluoropolymer. 7.The protective leaching mask assembly of claim 1, wherein the obliqueangle between the central axis of the superabrasive element and at leasta portion of the outer surface of the sidewall is between about 1 degreeand about 10 degrees.
 8. The protective leaching mask assembly of claim1, further comprising a binding member positioned on the at least onesidewall of protective mask proximate to the superabrasive table,wherein the binding member compresses the outer surface of theprotective mask.
 9. The protective leaching mask assembly of claim 8,wherein the binding member includes a ring-shaped member.
 10. Theprotective leaching mask assembly of claim 8, wherein the binding memberincludes at least one of polyphenylene, polypropylene,polytetrafluoroethylene, or ultra-high-molecular-weight polyethylene.11. The protective leaching mask assembly of claim 1, wherein theleaching agent is an acid or a base.
 12. A protective leaching maskassembly, comprising: a superabrasive element including a central axisand a superabrasive table; a protective mask covering at least a portionof the superabrasive element, the protective mask being chemicallyresistant to a leaching agent and including: a base portion; and atleast one sidewall extending from the base portion and defining anopening generally opposite the base portion, the at least one sidewallincluding: an inner surface abutting a selected portion of thesuperabrasive element; and an outer surface sloping at an oblique anglerelative to the central axis of the superabrasive element; and a bindingmember adjacent to the outer surface of the at least one sidewall, thebinding member compressing the inner surface against the selectedportion of the superabrasive element.
 13. The protective leaching maskassembly of claim 12, wherein the binding member is interference fittedwith the outer surface of the at least one sidewall and the interferencefit between the binding member and the outer surface is between about0.0001 inches and about 0.10 inches.
 14. The protective leaching maskassembly of claim 5, wherein the superabrasive table includes asuperabrasive table side surface defining a table outer diameter,wherein the substrate side surface defines a substrate outer diameterthat is substantially the same as the table outer diameter.
 15. Theprotective leaching mask assembly of claim 1, wherein the central axisis substantially parallel to an outer side surface of the superabrasiveelement.
 16. The protective leaching mask assembly of claim 12, whereinthe superabrasive element includes a substrate bonded to a superabrasivetable, wherein the substrate includes a substrate side surface defininga substrate outer diameter, wherein the superabrasive table includes atable side surface defining a table outer diameter that is substantiallythe same as the substrate outer diameter, wherein the selected portionincludes at least a portion of the substrate side surface of thesubstrate.
 17. The protective leaching mask assembly of claim 12,wherein the superabrasive element includes a substrate bonded to asuperabrasive table, wherein the superabrasive table includes a tableside surface defining a table outer diameter, wherein the substrateincludes a substrate side surface defining a substrate outer diameterthat is substantially the same as the table outer diameter.
 18. Theprotective leaching mask assembly of claim 12, wherein the inner surfaceand the outer surface of the at least one sidewall define a thickness,wherein the thickness is greater proximate to the opening than the baseportion of the protective mask.
 19. The protective leaching maskassembly of claim 12, wherein the inner surface of the protective maskis bonded to the selected portion of the superabrasive element via atleast one of a mechanical bond or a chemical bond.
 20. The protectiveleaching mask assembly of claim 12, wherein the protective mask coveringat least a portion of the superabrasive element is overmolded onto theat least a portion of the superabrasive element.
 21. The protectiveleaching mask assembly of claim 12, wherein the binding member isinterference fitted with the outer surface of the at least one sidewall.
 22. The protective leaching mask assembly of claim 12, wherein thebinding member includes polytetrafluoroethylene, polyphenylene,polypropylene, ultra-high-molecular weight polyethylene, metals, alloys,composite materials, or combinations thereof.
 23. The protectiveleaching mask assembly of claim 12, wherein the binding member includesa shape memory material.
 24. The protective leaching mask assembly ofclaim 12, wherein the binding member and the protective mask are formedfrom different materials.
 25. The protective leaching mask assembly ofclaim 12, wherein the binding member exhibits a greater flexural modulusthan the protective mask.
 26. The protective leaching mask assembly ofclaim 25, wherein the binding member exhibits a flexural modulus that isat least three times greater than a flexural modulus of the protectivemask.
 27. The protective leaching mask assembly of claim 25, wherein thebinding member exhibits a flexural modulus that is about two times toabout six times greater than a flexural modulus of the protective mask.28. The protective leaching mask assembly of claim 12, wherein thebinding member includes one or more resilient materials configured toapply a compressive force against the protective mask.
 29. Theprotective leaching mask assembly of claim 28, wherein the protectivemask exhibits a greater flexural modulus than the binding member. 30.The protective leaching mask assembly of claim 29, wherein theprotective mask member exhibits a flexural modulus that is at leastthree times greater than a flexural modulus of the binding member. 31.The protective leaching mask assembly of claim 29, wherein theprotective mask exhibits a flexural modulus that is about two times toabout six times greater than a flexural modulus of the binding member.32. The protective leaching mask assembly of claim 12, wherein thebinding member overlaps more than half of the at least one sidewall ofthe protective mask.
 33. The protective leaching mask assembly of claim12, wherein the binding member is positioned about a periphery of a topregion of the protective mask.
 34. The protective leaching mask assemblyof claim 12, wherein the binding member exhibits a ring-shapedconfiguration.
 35. A protective leaching mask assembly, comprising: asuperabrasive element including a central axis, a superabrasive table, asubstrate bonded to the superabrasive table, and an outer side surface,the central axis being substantially parallel to the outer side surfaceof the superabrasive element; a protective mask overmolded onto at leasta portion of the superabrasive element, the protective mask beingchemically resistant to a leaching agent and including: a base portion;and at least one sidewall extending from the base portion and definingan opening generally opposite the base portion, the at least onesidewall including: an inner surface that abuts with a selected portionof the superabrasive element; and an outer surface sloping at an obliqueangle relative to the central axis of the superabrasive element.
 36. Theprotective leaching mask assembly of claim 35, wherein the superabrasiveelement is generally cylindrical.
 37. The protective leaching maskassembly of claim 35, further comprising a binding member positionedabout the at least one sidewall of protective mask proximate to thesuperabrasive table, wherein the binding member compresses theprotective mask against the superabrasive table.